Device for charging metallurgical and like furnaces



April 6, 1926. 1,579,970

F. THARALDSEN DEVICE FOR CHARGING METALLURGICAL AND LIKE FURNACES FiledFeb. 9, 1923 Patented Apr. 6, 19 26.

FILIP THARALDSEN, OF BIES'JPUN', NEAR CHRISTIANIA, NORWAY.

DEVICE FOR CHARGING METALLURGICAL AND LIKE FURNACES.

Application filed February 9, 1923. Serial no; 618,118.

To all whom it may concern:

Be it known that I, FILIP THAnALnsnN, a citizen of Norway, and residingat Bestun, near Christiania, Norway, have invented certain new anduseful Improvements in Devices for Charging Metallurgical and like;

' tube to the one end'of which the material is able to escape or withoutpermitting the enconveyed from funnels or some other charge devices. Thescrew has then to transport the charge to the chamber where thematerials are to be-treated. Devices of this kind can often be used inroasting furnaces and other metallur ical furnaces where it isimperative that t e operation takes place without the gas from thefurnace chamber being trance of air from outside. The feeding screwshitherto used have, however, the considerable inconvenience that thegranulous or powdery materials of the charge will pack so firmly in thefeeding" tube that the movement of the screw is greatly hindered, or thescrew is even stopped. If it is tried to force the screw, it will easilybreak.

These inconveniences are obviated by the present invention whichconsists in that the screw has not the samepitch of the thread allthrough the feeding tube, but the pitch is greater further on in thetube than at the beginning and end of it where the charge materials areintroduced into and charged from the feeding tube. In this latter placethe charge materials must form a seal against the outside air, and thefeeding tube must here be filled with materials. Ow-- ing to the greaterpitch of the screw further on in the tube the materials will here get aquicker movement, and the feeding tube will thus not be quite filled.The danger of the screw being stopped by packed materials is reduced toa minimum by the fact that it is only in the very few threads of thescrew nearest to the charge funnel and the discharge end of the tubethat the materials are pressing on the screw.

It is not necessary that the pitch'of'the screw be increased all throughthe feeding tube. It is sufiicient to make the screw with two sections,a smaller pitch where the materials are received and discharged from thetube and one section with a greater pitch for the rest of the tube.

In any case the screw may of course be constructed in such a way thatthe pitch increases all through the tube.

In the accompanying drawings, Figure 1 is a diagrammatic longitudinalvertical section of a device embodying my invention.

Fig. 2 is a like view of modified form of the device. I

From the charge funnel A the materials are received by the feeding tubeB and fill the spaces between the threads of the feeding screw 0.Further on in the direction of the movement of the materials thesearrive to threads of a greater pitch, and the tube is therefore notquite filled here by the materials.

As shown in Fig. 1 the feeding screw has a less pitch of thread both inthe place, where the materials are delivered to the furnace, and at theentrance of the charge materials into the feeding tube, while theintermediate section of the screw has a greater pitch. The feeding tubewill then at both ends of it be filled with material. In this way asea'lis obtained also in the place where the materials are delivered to thefurnace chamber. This arrangement is of importance, when condensablevapours, for instance metal vapours are escaping from the furnacebecause otherwise such vapours would enter the feeding tube and condensethere.

Instead of one tube with a pitch of thread increasin' gradually or bysteps in the direction'of transport, the feeding device may as shown inFig. 2 consist of two or more tubes, that are passed one after anotherby the charge materials. In such case the first tube B may receive thematerial from the 1 charge funnel A and form a seal against the outsideair. This tube delivers the materials to a second tube B, thatconveniently is placed somewhat lower than the first one, and has ascrew with a greater pitch. In the second tube the materials areadvanced at a quicker rate and consequently the tube will nct betilledwith material; The second tube may be followed by a third one B,in

which the screw may again have .a-smaller pitch with lower transportcaptacity so that it) seal is' formed against the lrnacechamer. Y

I claim:

1. A feeding device for metallurgical fur-f" naces comprising acasmg'havmg a rece1v-- ing aperture at one end and a discharge apertureat the other end, a screw mecha nism in the casing the pitch of thescrewthread being smaller at both ends'than the intermediate portion ofthe screws 2. A feeding device for metallurgical furnaces comprisinga'tube having apertures forreceiving and discharging the material, afeed screw in the tube having the pitch of its thread smaller where thematerial is re- .ceived and delivered than at the intermedi- 20 ate partof the screw.

In witnesswhereof I afiix my signature.

FILIP THARALDSEN.

